Improvement in oxidative stability of fish meal by addition of glucose via accelerated Maillard reaction.

Abstract

The oxidative stability of sardine meal and oil mixed with the stick water browned by the Maillard reaction was compared with that of the meal and oil supplemented with synthetic anti-oxidants such as BHA and ethoxyquin. Browned stick water was prepared by the reaction be-tween added glucose and amino compounds in stick water at 80-120°C. The inhibitory effect was evaluated by measurement of oxygen absorption by fish meal or oil contained in a sealed flask and stored at 37°C in the dark. The ratio of oxygen/nitrogen in the head space of the flask was periodically determined by gas chromatography with a thermal conductivity detector. The antioxidative effect of stick water on fish oil and meal was remarkably enhanced with the progress of browning and nearly proportional to browning intensity. The oxidative stability of fish meal produced from press cake and the browned stick water with E4%1cm 0.28 at 420nm was comparable to that containing 0.01% ethoxyquin. After the Maillard reaction, the content of histidine, the most abundant free amino acid, and histamine in stick water decreased significantly. The decrease of these two imidazole compounds is preferable because these can produce gizzerosine which strongly induces Gizzard erosion in chicks.